In order to clarify lithofacies development characteristics and oil-bearing property of Permian Fengcheng Formation shale in Hashan area on northwest margin of Junggar Basin,geological characteristics of lithology,distri-bution and sedimentary environment of shale intervals in Fengcheng Formation are studied via outcrop,drilling,seismic and geochemical data analysis,and source rock quality,reservoir characteristics and gas-bearing property are analyzed.The results show that Fengcheng Formation shale is characterized by relatively high organic matter abundance with w(TOC)of 0.12%～5.13%,averaging 1.16%,being a set of immature-low mature source rock mainly composed of type Ⅰ and Ⅱ1 kerogen.Its residual hydrocarbon content is low and mainly as absorbed oil with high volume fraction averagely 72.57%.Pore size is mainly mesopores with volume fraction of 40.68%～83.98%,averaging 66.25%,and secondly micropores.6 lithofacies mainly develop in Fengcheng Formation shale,including dolomitic tuff,calcareous tuff,tuffaceous mud shale,dolomitic mud shale,calcareous mud shale and dolomitic siltstone,among which calcareous mud shale is dominant lithofacies with the most developed reservoir space and mainly composed of intergranular pores of quartz and intergranular pores of carbonate,with relatively high volume fraction of micropores and the highest average plane porosity of 9.97%.Calcareous mud shale has the highest shale oil content with w(TOC)of>2%and free oil content of>1 mg/g.The research provides reference for evaluation of shale oil-bearing property of Hashan and other areas.
维普
万方数据